Nancy Marshall offered her services on care.com. The site connects families with babysitters and pet sitters.

“I was so excited to make some money and help someone out,” said Marshall.

Marshall said someone wanted to hire her to dog sit for at least a week.

“She gave me her address. (She said) that she was going to move, which was right down the street,” Marshall said.

The woman sent Marshall a picture of herself with the dog, and wanted to pay up front to cover extras.

“I'll be sending you a check. I'll send extra money so you can buy dog food and a crate,” Marshall said.

A check arrived in the mail for more than $2,400, and that's when Marshal said she took a deep breath.

“A lot of red flags were going off,” she said.

It's a fraudulent check scam.

Action 9 found out that if Marshall had deposited the check, the woman hiring her would have asked for a partial refund. Two weeks later, the check would have bounced, and Marshall would have lost the money she had refunded.

Action 9 reviewed complaints on care.com from babysitters and pet sitters who had fallen for the scam.

Holly Salmons, with the Central Florida Better Business Bureau, said people looking for part-time money can be very vulnerable to the online scheme.

“So by the time the check bounces, you are left not only covering fees, but sending your money to someone ripping you off,” Salmons said.

Care.com told Action 9 that it has added security measures to block fraud. The company said anyone who enrolls for a job is sent a letter about how to spot and avoid scams.

Marshall never cashed the check.

“They're going to take your money,” Marshall said.

Care.com sent Action 9 this response:

“Unfortunately, scams of this nature are prevalent across the internet. Care.com takes this issue seriously, and we take a variety of steps to educate the caregivers on our site they can spot and avoid scams, including:

As part of enrolling on care.com, everyone receives a letter detailing how to recognize scams and steps to take to protect themselves.